Ovarian stimulation outcomes improve on successive retrieval cycles regardless of change in gonadotropin dose or protocol

Objective: To investigate whether particular changes in gonadotropin dose or stimulation protocols can improve ovarian stimulation outcomes for patients undergoing successive retrieval cycles.

Materials and Methods: We analyzed 64,585 patients with multiple completed retrieval cycles from 2014-2019 in the Society for Assisted Reproductive Technology Clinical Outcomes Reporting System (SART CORS). The primary outcomes were the number of eggs retrieved, 2PNs, and blastocysts (transferred plus frozen). Comparison of outcomes between successive cycles may be biased by the decision to stop or continue treatment. To help mitigate this bias, we compared outcomes between the first and second cycles among (a) patients with two or more successive cycles, and (b) patients with three or more successive cycles. Lastly, we stratified outcomes by patients given more or less FSH per day on their second cycle, and by patients with or without protocol changes between cycles. Results were calculated for four quantiles of patient AMH (ng/mL) at the start of the first cycle.

Results: On average, patients retrieved more eggs and created more 2PNs and blastocysts on their second cycle compared to their first cycle, regardless of change in FSH dose. Patients who changed protocols between first and second cycles had a greater improvement in outcomes.

Conclusions: We observed improvements in outcomes between first and second retrieval cycles regardless of change in dosing or protocol. Future work should further investigate whether these findings are due to patient behaviors (such as better adherence to medication or reduced stress), an inherent biological factor such as ovarian priming, or lessons learned by clinicians from first cycle outcomes.

Impact Statement: Patients who decide to undergo multiple retrieval cycles appear on average to have slightly more eggs, 2PNs, and blastocysts on their second retrieval.